Carpet is a common floor covering used in many businesses and residences. While well-made carpet is generally versatile and long-lasting, carpet waste nonetheless represents a growing concern in both private industry and governments. Carpet waste can include, for example, post consumer carpet, including commercial, industrial and residential waste carpet; manufacturing remnants; quality control failures, and the like. Waste carpet can be used carpet, e.g., carpet removed from an apartment complex, or unused carpet, e.g., residual carpet left from an installation or manufacturing process.
Unfortunately, the vast majority of current carpet waste is sent to landfills for disposal. While most estimates indicate that carpet waste constitutes only 1 to 2% of all municipal solid waste, this amount still represents a vast quantity of waste that can have a substantial economic and environmental impact. As a result, many in the industry have turned to carpet recycling as a solution to carpet waste. Recycling carpet, however, is difficult because its major components are chemically and physically diverse. Most carpets comprise about 20-50 weight percent face fiber, the remainder being backing materials, commonly polypropylene, and an adhesive which attaches the carpet fiber to the backing material. The adhesive typically comprises a carboxylated styrene-butadiene (XSB) latex copolymer, and an inorganic filler such as calcium carbonate.
Most carpet recycling methods to date have focused on recycling certain environmentally malignant constituents of carpet. Examples include polymers, such as nylon, and adhesive constituents found in waste carpet. However, little attention has been devoted to the various other constituents of carpet, such as inorganic filler. While such constituents may not present a direct environmental harm, they nonetheless represent a potential cost savings and a reduction in landfilling burden. If such materials could be reclaimed and recycled, the supply of such materials could be augmented, thereby reducing the burden to manufacture new materials. In addition, such broad-based recycling methods can also potentially help to comport with National Sanitation Foundation (NSF) 140/2007 recommendations, which encourage carpet industries to develop sustainable carpet manufacturing and recycling programs for social, economic, and environmental benefits. Accordingly, there is a need to provide improved methods and systems for recycling one or more component parts of carpet.
Rebond foam or rebond polyurethane foam is known in the art of isocyanate-based polymeric foams. Specifically, it is known to mix pre-formed pieces or chunks of foam with a binder component that serves to bond the pre-formed foam pieces to one another. This so-called “rebonding” technology has been used for a number of years as a means for recycling waste polyurethane foams. Due to their relative high density and excellent resilience, rebond foams are suitable for applications including vibration sound dampening, flooring, sport mats, cushioning, packaging and carpet underlay. In fact, it is estimated that hundreds of thousands of tons of rebonded foam are produced each year.
The following invention is therefore based upon the unexpected discovery that various reclaimed carpet materials can be incorporated into these conventional rebond polyurethane foams as a filler. As discussed in greater detail below, the presence of reclaimed carpet material as a filler in conventional rebond polyurethane foams can improve dimensional stability, while replacing more expensive materials commonly used to manufacture first generation rebond. Moreover, this can be achieved without sacrificing the desirable performance properties of conventional rebond foam, including for example plushness or softness, dimensional stability, and tear resistance of the foam. Still further, due to the significant quantities of rebond foam manufactured yearly, the present invention also provides an improved method for recycling carpet material that avoids the cost and environmental impact associated with sending carpet waste to landfills.